I was putting a Pro Spring Kit in my Bisley last night, and somehow in the process of switching the trigger springs, the gate spring popped out from under the notch on the gate. When I got it back togeather, the gate was sticky, and when it was opened the cylinder wouldn't turn. It took me a while to notice what was wrong. Luckily, I had that little tool from Brownells that compresses the gate spring and holds it in place while you punch out the trigger pin. I got it fixed up, but the frustration level was high for a few minutes there. It doesn't look like there is room in that little notch for it to slip out under tension, and I was afraid that it was bent. Guess it was just me. The good news is that it did help the trigger pull.
